EPDM and rooflights

[Tetrarch]

I am a bit of an EPDM fanboy having installed a 45 sq m L-shaped flat roof covering myself back in the early 2000's

 

I've just had my extension built and I'm looking at a green roof and I'd like an EPDM roof covering. This time, I have parapet walls on either side and three 2m x 1m rooflights so I think I want professional assistance - this has proven tricky as EPDM installers seem to be thin on the ground.

 

This hasn't stopped my paranoia about leaks and I've been researching possible solutions. My biggest fear is around external corners (all 12 of them). The product that keeps coming up on "EPDM external corner" searches is this:

 

https://www.roofingsuperstore.co.uk/product/roofing-superstore-preformed-epdm-external-corner.html?msclkid=f30a00c1779a1c525f056695338aa4ec which seems to a patch stuck on top of the cut EPDM corner

 

I would have thought that a preformed corner UNDERNEATH the cut EPDM would be better

 

ANd now I've stumbled across this:

 

https://www.obexglobal.com/uk/products/epdm-and-interface-sealing-systems/obex-cortex-0901fr-external-pre-moulded-corners/

 

Is there any reason why this preformed corner would not be an excellent way to perfectly belt-and-braces waterproof a skylight? 

 

Regards

 

Tet

 

PS Edited to add a video illustrating exactly why this looks so good
 

 

Edited May 27 by Tetrarch
Addition

[Alan Ambrose]

I'm a fan of epdm too. In another recent thread, it was pointed out that it (at least some of it) can be hot welded. Robin Clevett has a video on a system - you might be able to pick up a few tips. Although it's branded 'Alwitra', I understand that it's epdm.

 

 

 

[EdHat]

Proper single ply membranes are often used on large flat roofs without complicated details for speed of insulation or pitch roofs as it presents a very clean look. These are usually PVC or TPO/FPO and are heat welded at laps which makes them very durable.

I see some issues with puncturing where people walk on it, but electronic testing can locate punctures and they can be patched.

Biggest issue I've seen is with poor installation where it wasn't adhered properly and blew off in a strong wind.

 

EPDM seems to be a more DIY suited product for use on simple small scale roofs i.e. garages, garden buildings. While the membranes seem to have a long life expectancy I'm not convinced the adhesives and trims do.

The EPDM trims do not seem durable to me as they sandwich the membrane and rely on foam for creating a seal.

Laps do not seem durable either as they use adhesive rather then heat welding. They are especially vulnerable on corners where they often start to open up so belt and braces would definitely be wise.

I  see a lot of rippling with EPDM that I haven't noticed with other single plys. 

EPDM is also much more vulnerable to puncturing then other single ply membranes.

 

Note the big manufacturers of single ply membranes, such as Sika, Icopal and Bauder don't produce EPDM membranes. The Alwitra one in featured in the Robin Clevett video is PVC.

 

I very much a fan of bitumen felts for 'out of site' flat roofs for their durability and cost effectiveness.

 

There are a lot of cold applied liquid systems on the market now with BBA certs to rival lifespan of other products which are excellent for complicated details and overcome many of the issues with GRP, but do come at a cost premium.